Using WeasyPrint for HTML to PDF Conversion (with examples)

WeasyPrint is a powerful command-line tool that allows users to convert HTML files to PDF or PNG format. In this article, we will explore eight different use cases of WeasyPrint by providing code examples, motivations, explanations of each argument, and examples of the output.

Render an HTML file to PDF

To convert an HTML file to PDF, we can use the following command:

weasyprint path/to/input.html path/to/output.pdf

Motivation: Converting HTML files to PDF format is often necessary for purposes such as creating printable versions of web pages, generating reports, or sharing documents that can be easily viewed across different devices and platforms.

Explanation:

• path/to/input.html: The path to the HTML file that needs to be converted to PDF.
• path/to/output.pdf: The path and filename of the PDF file that will be generated as the output.

Example Output: If we run the command weasyprint input.html output.pdf, it will convert the input.html file to output.pdf.

Render an HTML file to PNG with an additional user stylesheet

To convert an HTML file to PNG format and apply an additional user stylesheet, we can use the following command:

weasyprint path/to/input.html path/to/output.png --stylesheet path/to/stylesheet.css

Motivation: Including a custom stylesheet provides the ability to modify the styles (such as colors, fonts, or layout) of the HTML file before converting it to PNG format. This is useful for creating visually appealing snapshots of web pages.

Explanation:

• path/to/input.html: The path to the HTML file that needs to be converted to PNG.
• path/to/output.png: The path and filename of the PNG file that will be generated as the output.
• --stylesheet path/to/stylesheet.css: Specifies the path to an additional user stylesheet that will be applied to the HTML file before conversion.

Example Output: Running the command weasyprint input.html output.png --stylesheet styles.css will convert the input.html file to output.png, applying the styles defined in the styles.css stylesheet.

Output additional debugging information when rendering

To enable the output of additional debugging information during the rendering process, we can use the following command:

weasyprint path/to/input.html path/to/output.pdf --verbose

Motivation: Enabling verbose mode helps with troubleshooting rendering issues by providing detailed information about the rendering process, including warnings, errors, and specific steps taken. This can be particularly useful when dealing with complex HTML files or when the output does not match expectations.

Explanation:

• path/to/input.html: The path to the HTML file that needs to be converted to PDF.
• path/to/output.pdf: The path and filename of the PDF file that will be generated as the output.
• --verbose: Enables verbose mode, which will output additional debugging information during the rendering process.

Example Output: When the command weasyprint input.html output.pdf --verbose is executed, the tool will provide detailed information about the rendering process, such as element layout, applied styles, and any potential rendering errors or warnings.

Specify a custom resolution when outputting to PNG

To specify a custom resolution for the PNG output, we can use the following command:

weasyprint path/to/input.html path/to/output.png --resolution 300

Motivation: The default resolution of the PNG output generated by WeasyPrint is 96 DPI (dots per inch). By specifying a higher resolution, we can improve the image quality, especially when dealing with images or diagrams that require more detail.

Explanation:

• path/to/input.html: The path to the HTML file that needs to be converted to PNG.
• path/to/output.png: The path and filename of the PNG file that will be generated as the output.
• --resolution 300: Specifies the resolution in DPI (dots per inch) for the PNG output.

Example Output: By executing the command weasyprint input.html output.png --resolution 300, it will convert the input.html file to output.png with the specified resolution of 300 DPI.

Specify a base URL for relative URLs in the input HTML file

To specify a base URL for resolving relative URLs in the input HTML file, we can use the following command:

weasyprint path/to/input.html path/to/output.png --base-url url_or_filename

Motivation: When converting an HTML file to PDF or PNG, it’s common to encounter relative URLs within the file (e.g., for images, stylesheets, or other resources). By providing a base URL, WeasyPrint can correctly resolve these relative URLs, ensuring that the converted file includes the expected content.

Explanation:

• path/to/input.html: The path to the HTML file that needs to be converted to PNG.
• path/to/output.png: The path and filename of the PNG file that will be generated as the output.
• --base-url url_or_filename: Specifies the base URL (or local file path) for resolving relative URLs in the input HTML file.

Example Output: If we run the command weasyprint input.html output.png --base-url https://example.com/, WeasyPrint will convert the input.html file to output.png, correctly resolving any relative URLs using the provided base URL.

Conclusion

In this article, we explored eight different use cases of WeasyPrint, a powerful command-line tool for converting HTML files to PDF or PNG format. We covered commands for converting HTML files to PDF, including user stylesheets, enabling verbose mode for debugging, specifying custom resolutions for PNG output, and providing a base URL for resolving relative URLs. By understanding and utilizing these use cases, you can effectively leverage WeasyPrint for various HTML conversion needs.